[PATCH v1] i2c: geni: reset controller on NACK to recover from invalid bus state

[Aswin Murugan]

During i2c probe, repeated accesses to non-existent slave addresses
generate consecutive NACK responses. On GENI I2C controllers, these
back-to-back error conditions leaves the controller in an invalid
or busy state, especially at lower bus frequencies (100 kHz and
400 kHz). As a result, subsequent transfers fails and valid slave
addresses are not detected.

Currently, controller recovery is triggered only on timeout errors.
However, NACK conditions (-EREMOTEIO) can lead to the same stale bus
state.

Handle -EREMOTEIO similar to -ETIMEDOUT by issuing a command abort
before starting the next transfer. This ensures the controller state
machine is reset and the bus is returned to a known good state.

This improves reliability of i2c probe and allows correct detection
of slave devices under repeated probing conditions.

Signed-off-by: Aswin Murugan <aswin.murugan at oss.qualcomm.com>
---
 drivers/i2c/geni_i2c.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/i2c/geni_i2c.c b/drivers/i2c/geni_i2c.c
index fbe5ab0ad0c..7498cbcb41a 100644
--- a/drivers/i2c/geni_i2c.c
+++ b/drivers/i2c/geni_i2c.c
@@ -285,7 +285,7 @@ static int geni_i2c_xfer(struct udevice *bus, struct i2c_msg msgs[], int num)
 	}
 
 	if (ret) {
-		if (ret == -ETIMEDOUT) {
+		if (ret == -ETIMEDOUT || ret == -EREMOTEIO) {
 			u32 status;
 
 			writel(M_GENI_CMD_ABORT, geni->base + SE_GENI_M_CMD_CTRL_REG);
-- 
2.34.1